Is 5 + 3(1 - x) equivalent to 8 -8x

Distributeive property
a(b-c)=ab-ac
so
first distribute
3(1-x)=3-3x

now we has
5+3-3x
8-3x

it is not equal to 8-8x

So to see if they are equivalent you need to simplify the first one
start with distributing the 3 to 1 and -x
so 5 + 3 -3x does it equal 8 - 8x?
next you combine like terms 
8 - 3x
so they aren't equivalent
8 - 3x ≠ 8 - 8x

Hope this helps ;)

The answer maybbe c